our app is a "in-memory" service application (but their is one table with a good deal of data used for personalization) and we don't use service builder; surely the marketplace can accommodate 5 minute configuration process.

You might not blink at a 5 minute outage, but I'd have folks beating on my door if our site was down...

Note I speak for myself, and not Liferay or other marketplace downloaders...

For only a single entity, a SB implementation would not seem to be that big of a deal... An alternative would, of course, be portlet preferences. A nice little prefs page for admins to set what they want, apply to the portlet, no SB or JNDI config required, and no outages on my end to deal with...